// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/device_monitors/system_message_window_win.h"

#include <dbt.h>
#include <stddef.h>

#include "base/logging.h"
#include "base/macros.h"
#include "base/system_monitor/system_monitor.h"
#include "base/win/wrapped_window_proc.h"
#include "media/audio/win/core_audio_util_win.h"

namespace media {

namespace {
    const wchar_t kWindowClassName[] = L"Chrome_SystemMessageWindow";

    // A static map from a device category guid to base::SystemMonitor::DeviceType.
    struct {
        const GUID device_category;
        const base::SystemMonitor::DeviceType device_type;
    } const kDeviceCategoryMap[] = {
        { KSCATEGORY_AUDIO, base::SystemMonitor::DEVTYPE_AUDIO },
        { KSCATEGORY_VIDEO, base::SystemMonitor::DEVTYPE_VIDEO_CAPTURE },
    };
} // namespace

// Manages the device notification handles for SystemMessageWindowWin.
class SystemMessageWindowWin::DeviceNotifications {
public:
    explicit DeviceNotifications(HWND hwnd)
        : notifications_()
    {
        Register(hwnd);
    }

    ~DeviceNotifications() { Unregister(); }

    void Register(HWND hwnd)
    {
        // Request to receive device notifications.  All applications receive basic
        // notifications via WM_DEVICECHANGE but in order to receive detailed device
        // arrival and removal messages, we need to register.
        DEV_BROADCAST_DEVICEINTERFACE filter = { 0 };
        filter.dbcc_size = sizeof(filter);
        filter.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
        bool core_audio_support = media::CoreAudioUtil::IsSupported();
        for (size_t i = 0; i < arraysize(kDeviceCategoryMap); ++i) {
            // If CoreAudio is supported, AudioDeviceListenerWin will
            // take care of monitoring audio devices.
            if (core_audio_support && KSCATEGORY_AUDIO == kDeviceCategoryMap[i].device_category) {
                continue;
            }

            filter.dbcc_classguid = kDeviceCategoryMap[i].device_category;
            DCHECK_EQ(notifications_[i], static_cast<HDEVNOTIFY>(NULL));
            notifications_[i] = RegisterDeviceNotification(
                hwnd, &filter, DEVICE_NOTIFY_WINDOW_HANDLE);
            DPLOG_IF(ERROR, !notifications_[i])
                << "RegisterDeviceNotification failed";
        }
    }

    void Unregister()
    {
        for (size_t i = 0; i < arraysize(notifications_); ++i) {
            if (notifications_[i]) {
                UnregisterDeviceNotification(notifications_[i]);
                notifications_[i] = NULL;
            }
        }
    }

private:
    HDEVNOTIFY notifications_[arraysize(kDeviceCategoryMap)];

    DISALLOW_IMPLICIT_CONSTRUCTORS(DeviceNotifications);
};

SystemMessageWindowWin::SystemMessageWindowWin()
{
    WNDCLASSEX window_class;
    base::win::InitializeWindowClass(
        kWindowClassName,
        &base::win::WrappedWindowProc<SystemMessageWindowWin::WndProcThunk>, 0, 0,
        0, NULL, NULL, NULL, NULL, NULL, &window_class);
    instance_ = window_class.hInstance;
    ATOM clazz = RegisterClassEx(&window_class);
    DCHECK(clazz);

    window_ = CreateWindow(kWindowClassName, 0, 0, 0, 0, 0, 0, 0, 0, instance_, 0);
    SetWindowLongPtr(window_, GWLP_USERDATA, reinterpret_cast<LONG_PTR>(this));
    device_notifications_.reset(new DeviceNotifications(window_));
}

SystemMessageWindowWin::~SystemMessageWindowWin()
{
    if (window_) {
        DestroyWindow(window_);
        UnregisterClass(kWindowClassName, instance_);
    }
}

LRESULT SystemMessageWindowWin::OnDeviceChange(UINT event_type, LPARAM data)
{
    base::SystemMonitor* monitor = base::SystemMonitor::Get();
    base::SystemMonitor::DeviceType device_type = base::SystemMonitor::DEVTYPE_UNKNOWN;
    switch (event_type) {
    case DBT_DEVNODES_CHANGED:
        // For this notification, we're happy with the default DEVTYPE_UNKNOWN.
        break;

    case DBT_DEVICEREMOVECOMPLETE:
    case DBT_DEVICEARRIVAL: {
        // This notification has more details about the specific device that
        // was added or removed.  See if this is a category we're interested
        // in monitoring and if so report the specific device type.  If we don't
        // find the category in our map, ignore the notification and do not
        // notify the system monitor.
        DEV_BROADCAST_DEVICEINTERFACE* device_interface = reinterpret_cast<DEV_BROADCAST_DEVICEINTERFACE*>(data);
        if (device_interface->dbcc_devicetype != DBT_DEVTYP_DEVICEINTERFACE)
            return TRUE;
        for (const auto& map_entry : kDeviceCategoryMap) {
            if (map_entry.device_category == device_interface->dbcc_classguid) {
                device_type = map_entry.device_type;
                break;
            }
        }

        // Devices that we do not have a DEVTYPE_ for, get detected via
        // DBT_DEVNODES_CHANGED, so we avoid sending additional notifications
        // for those here.
        if (device_type == base::SystemMonitor::DEVTYPE_UNKNOWN)
            return TRUE;
        break;
    }

    default:
        return TRUE;
    }

    monitor->ProcessDevicesChanged(device_type);

    return TRUE;
}

LRESULT CALLBACK SystemMessageWindowWin::WndProc(HWND hwnd,
    UINT message,
    WPARAM wparam,
    LPARAM lparam)
{
    switch (message) {
    case WM_DEVICECHANGE:
        return OnDeviceChange(static_cast<UINT>(wparam), lparam);
    default:
        break;
    }

    return ::DefWindowProc(hwnd, message, wparam, lparam);
}

} // namespace media
